Conventionally, microfabrication has been carried out by lithography using a photoresist in the production of semiconductor devices. The microfabrication is a processing method including forming a thin film of a photoresist on a semiconductor substrate such as a silicon wafer, irradiating the thin film with active light such as ultraviolet rays through a mask pattern on which a pattern of a semiconductor device is depicted, developing the pattern, and etching the substrate by using the obtained photoresist pattern as protection films, so that fine concavity and convexity, which correspond to the pattern, is formed on the surface of the substrate. In recent years, however, semiconductor devices tend to be further integrated, and the active light to be used has had a shorter wavelength from a KrF excimer laser (248 nm) to an ArF excimer laser (193 nm). This raises serious problems of the effects of reflection of active light from the semiconductor substrate. Thus, lithography of multilayer resist process using hardmasks has been carried out.
As a resist underlayer film containing a metal other than silicon, use of a compound obtained by mixing metal alkoxy that contains metal, such as tungsten, zinc, aluminum, and indium, and silicon alkoxide; and then hydrolyzing the mixture for an inorganic film for a multilayer resist process, is disclosed (see Patent Document 1).
A metal oxide film containing single metal, such as zirconium, molybdenum, and hafnium; metal oxoacid, metal oxide, metal hydroxide, metal alkoxide, metal halide, and metal oxyhalide is disclosed (see Patent Document 2).
A composition for forming tungsten oxide films containing water soluble metatungstate and at least one additive selected from anionic polymers, nonionic polymers, anionic surfactants, and nonionic surfactants containing tertiary amino groups, is disclosed (see Patent Document 3).
A method for forming patterns, in which a silicon-containing film is formed on the top surface of a substrate to be processed by using a polysiloxan composition, and by adding an acid, a base, a metal complex, a metal salt compound, and an onium salt compound is disclosed. As the acid, hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, hydrosulfuric acid, perchloric acid, hydrogen peroxide, carbonic acid, formic acid, acetic acid, benzenesulfonic acid, phosphoric acid, heteropoly acid, an inorganic solid acid, and the like are disclosed (see Patent Document 4).